Update:
Seems T-Mobile has priced Lumia 521 $199 without any annual contract (Prepaid). As a limited time offer they are also offering $50 refill card. Though it is not known whether this prepaid version of Lumia 521 will only work with T-Mobile or with other operators as well.
Those who are eagerly waiting for Lumia 521 in US, and couldn’t grab one due to stock outs at HSN and Walmart has to look no further than T-Mobile itself now. Lumia 521 can now be booked from the carrier website for full price of $149 or on down payment of $29 for a monthly payment plan of just $5 for 2 years. This is valid with wireless plans of T-Mobiles. We are sure the device will see similar strong demand at T-Mobile as it has seen on both HSN and Walmart. The real question remains, has T-Mobile got enough stock ?